a) Field of the Invention
The invention relates to a method and apparatus for removing and installing a differential from and to a vehicle where the differential and a hoisting assembly supporting the differential are supported by the frame of the vehicle.
b) Background Art
The prior art disclosures are primarily directed toward supporting a differential by applying a force to elevate and support the differential where the surrounding ground surface is the primary direct area for support. For example, the following prior art referenced as are discussed herein below.
U.S. Pat. No. 6,322,061 (Maser et al) discloses a “Universal Axle and Differential Carrier Stand”. The disclosure shows a wheeled base frame having two upper horizontal support rails 12 to which are mounted vertically aligned support arms 24 which are adjustably mounted by sliding supports 25. At the upper end of these arms are a pair of axle clamp assemblies 30 which fit into the members 24 so that these can be placed at different elevations. FIG. 3 shows the apparatus supporting the differential 70.
U.S. Pat. No. 5,566,999 (Goettl) relates to a particular type of mechanism by which the differential can be lifted. In column 1, under “Background of Invention,” beginning on line 36, it is stated that it is a common practice to weld a lifting eye or loop to an exterior of the case of the differential, and this can be used to accept the hook of a hoist. It is indicated that this is done by welding, and this can weaken the case of the differential at that point. The disclosure is directed to the particular type of hoist attaching mechanism, and this comprises upper and lower jaws 20 and 22 which grip the flange of the differential, and there are also various bolt connections.
Other US patents disclose various methods of supporting a differential such as U.S. Pat. No. 4,570,905 (Gerstner) shows a floor jack attachment which is intended to be used as a means to hold and move a differential. U.S. Pat. No. 4,549,722 (Gagliano) shows a floor jack that is intended to be used to support a differential as it is removed. U.S. Pat. No. 3,559,981 (Abshear) shows a wheeled device that is secured to a differential, and used to remove it from the housing.
U.S. Pat. No. 3,012,311 (Shupe) provides yet another differential support intended to be secured to a jack on the floor. U.S. Pat. No. 2,903,258 (Jonanovich) shows a repair stand that may be secured to a floor jack to move the differential about the shop. Finally, U.S. Pat. No. 2,748,459 (Orr) shows a jack attachment intended to support a differential.